Trimingham Radar Fault: The MoD Stance

In the last issue of UFOData Magazine (Jan/Feb 2007), we looked at the instances of car breakdowns caused by a faulty radar at Trimingham in Norfolk. Using the Freedom of Information Act (FOIA), we put in a request to the Ministry of Defence (MoD) for the results of their inquiry into the fault. They replied surprisingly quickly (but not quickly enough to appear in the last issue) and there were some surprising elements in the documents sent to us.

With government documents covered under the Crown Copyright, we cannot reprint them in full (it’s twenty-odd pages anyway), but reproducing extracts is permitted.

In February, 2006, a Unit Inquiry (UI) began and MoD officials began collating data. They amassed material from within the ministry, as well as newspaper reports and statements from both serving personnel and private citizens.

In the findings of their report, the board first gave some background to the Trimingham site, describing its location on the B1159 road between Cromer and Mundesley in Norfolk, and that the Type-93 radar was first installed there in April, 1997. Engineering responsibility for Remote Radar Head (RRH) Neatishead and RRH Trimingham is held by RAF Scampton.

The attributes of the Type-93 radar are then listed, explaining that it consists of 96 elements, each of which can receive and transmit radio energy. The elements are mounted on a coiled component called the ‘Serpentine’ and in between each element is a Phase Shifter. There are 96 Phase Shifters and it is these that focus the radio energy into a beam. Special software called DREAM (Digital Recording Equipment for Analysing Messages) has been designed to analyse the data output of the radar and find any faults.

In November, 2005, the operators at Trimingham began noticing a decrease in height accuracy coming from the array and were forced to us the Multi-Scan Correlator to correct the errors.

In January, 2006, the continuing errors and the complaints coming from local residents about their vehicles developing problems led operators to believe that a fault had occurred in the Waveguide Pressurisation System. Efforts were made to avoid transmitting over the B1159 road and checks were made every 3 hours.

In February, 2006, work began to locate the faults and it was discovered that almost a third (about 30) of the Phase Shifters were found to be unserviceable. Apparently this is a common problem with the ITT-made Type-93 radars fleet. At the same time, radiation hazard tests were conducted, both on the site and also on the B1159 road. No dangerous levels were discovered. The faulty Phase Shifters were replaced and a pressure switch was fitted to the Waveguide Pressurisation System to allow radar transmissions to be cut-off if the pressure fell too low.

The board summarised their conclusions as:

 It is not possible to exactly determine the radar effects on motor vehicles in question. This Unit Inquiry cannot dismiss the apparent coincidence of known radar faults on the Type 93 radar at Trimingham and a dramatic increase in vehicle electromagnetic interference. Moreover, the cessation of vehicle incidence reporting correlates with the radar's return to serviceability (a fact which was not readily known within the local population). It is therefore reasonable to suggest, on this information alone, that the radar was the probable cause of the reported car interference effects.

They also noted that use of the Multi-Scan Correlator to correct the faulty height data inhibited the DREAM software from finding any fault.

Between 7th and 11th of November, 2005, Radiation Hazard (RadHaz) tests were conducted to ascertain if there was any danger to the local population. Make of the following section what you will:

The Report showed that all non-ionizing RadHaz measurements, made at the Trimingham Site, were within the limits set by the National Radiological Protection Board (NRPB); with the exception of a single measurement taken at the B1159 Lay-By which indicated an above-average radiation level. It is also noted that the DCTO Report highlighted this reading as a 'spurious emission' which, according to the Report, wasn't likely to have been generated from the Type 93 Radar at RRH Trimingham.

A further test was done in February, 2006, and it was decided that the readings from the November survey were in error and that radiation levels were far below danger levels.

The MoD received only five claims for compensation, totalling £1908.43, from members of the public and the board ruled that those payments should be made.

Other recommendations included the removal of radiation warning signs on the MoD fence along the B1159.

The Unit Commander, a wing commander at RAF Scampton, concurred with the Board of Inquiry (BoI) that the incidents were unforeseen and that the Trimingham radar was likely the cause of the motor vehicle incidents. That said, he went on to declare that “I agree that there was no hazard to either humans or equipment.”
The Air Surveillance And Control System (ASACS) Force Commander from RAF Boulmer also agreed with the BoI findings and revealed that the following measures had been implemented:

An excel spreadsheet has been created to document the Phase Shifter Loads thereby enabling the timely identification of failing Phase Shifters. The 4th Line Field Service Engineer has control of the document and the data is generated each quarter. A thermal camera will now be used to identify the excess heat symptomatic of a failing Phase Shifter (a thermal camera is being procured by the Air Defence Ground Based Systems Integrated Project Team (ADGBS IPT)). DREAM recordings are also being taken on site every 24 hours, which should assist in identifying height errors.
The ADGBS IPT has reviewed all documentation and is content that the engineering procedures are robust. Procedures for use of the thermal camera will be produced by the ADGBS IPT following testing.
Training for the use of the thermal camera will be arranged by the ADGBS IPT. All Type 93 radar technicians are now trained in conducting the required DREAM recordings and the ASACS Role Office will review the recordings during their regular External Quality Audits.

He also noted that the president of the BoI had since been posted overseas…

So there we have it. The Type-93 radar fleet is prone to breaking down and in this case, almost a third of the Phase Shifters failed. The actions taken to alleviate the faulty equipment resulted in the diagnostic software being unable to detect the fault and, thus, reports began to come in from members of the public, whose cars began conking out.

Despite this, the MoD declared that radiation levels were not dangerous and that no damage to MoD or private property had occurred, even though compensation claims had been received. They were lucky to get only five, when, according to Neil Crayford of the Crayford & Abbs garage in nearby Mundesley, dozens of vehicles had been affected and are still being affected.

How does a RadHaz team find that radiation levels on site are below danger levels, but in a lay-by on the B1159, they are ‘above average’? A second test several months later finds that levels are ‘well below’ danger levels and, therefore, the earlier readings must have been erroneous! Is it possible a car was zapped in the lay-by, was towed away or left under its own power and a residual radiation reading was left behind, only for it to have gone by the time of the second RadHaz tests? Or was there something else in that lay-by, as the report stated that the radiation reading ‘wasn't likely to have been generated from the Type 93 Radar at RRH Trimingham’?

Why remove the radiation warning signs from the fence and, if there was no danger to the public, why were they there in the first place?

If any of our readers are familiar with the practices at our radar sites, perhaps they could drop us a line in the usual way and let us know what they thought about what went on at RRH Trimingham.

Hopefully, with the new implementations, all is well in that part of Norfolk, despite Mr Crayford saying that about two cars every ten days are still coming in after experiencing problems after driving by the Trimingham site.

UFOData Magazine would like to thank the Ministry of Defence for its quick reply to our FOAI request.

Steve Johnson


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Updated 16th August, 2012